Replacement of a diseased or malfunctioning cardiac valve requires accurate sizing of the valve annulus. After the diseased or malfunctioning cardiac valve has been removed, the surgeon measures the patient's valve annulus to determine the appropriate replacement valve size.
A conventional system for measuring a patient's valve annulus includes a number of varying size discs which can be attached to a rod. Each of the discs has a size which corresponds to an available valve size. The surgeon attaches one of the discs to the rod, inserts the disc into the patient's valve annulus and checks the fit of the disc within the valve annulus. If the surgeon is not satisfied with the fit, the surgeon removes the disc from the rod, attaches another disc to the rod and inserts the new disc into the valve annulus. This procedure is repeated until the surgeon is satisfied that the appropriate valve size has been identified.
A problem with the known method and apparatus for sizing a patient's valve annulus is the time required to try a number of discs. For each valve size the surgeon tries, the surgeon must remove one of the discs and attach another one. This procedure increases the overall surgery time which increases the risk to the patient and also increases the cost of the procedure.
Thus, it is a specific object of the present invention to reduce the amount of time required to size a patient's valve annulus by providing a device which can identify a number of different appropriate valve sizes without requiring withdrawal of the device from the patient.